If you search the "conversion" threads... I think someone lately has said they come out easily... and if the car you have was offered with manual trans that that mounting hardware it there to put then to.... might be time to crawl upside down into your drivers side foot space and look up with a flashlight.... if you study the drawings for what it fits to ( or look closely on your parts car ) it may be easier to spot the brackets...
If you take all the associated stuff out and offer it to the forum I expect you can get between $500 and $700 for it.. ( maybe more )... something to think about.... So even if they will not go into YOUR car... they may be worth pulling at the price you were quoted for the trans....
One thought.. make a deal for all the stuff that goes with it first... then ask if they will turn the car on its side... talk about easy access...

LOL, Ben posted while I was composing...

Ben, what about whether it will ' bolt' into his car ?